This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of the protocol is to obtain prospective data about postoperative corticosteroid use in neonates with congenital heart disease. Our hypothesis is that postoperative treatment with corticosteroids will allow weaning of inotropic agents and improve postoperative hemodynamics. Corticosteroids have been shown to improve blood pressure and hemodynamics in patients with sepsis with a systemic inflammatory response and in premature neonates. There is one retrospective study in pediatric postoperative patients with congenital heart disease who received corticosteroids. This study showed improvements in blood pressure. There have been no definitive studies as to the method of action of corticosteroids in postoperative low cardiac output syndrome. Patients will be selected prospectively after meeting a level of inotrope requirement postoperatively to be included in the study. They will be randomized to receive corticosteroids or placebo and then will be followed to determine hemodynamic effects and possible methods of action. We hypothesize that patients who receive corticosteroids will wean off inotropes sooner than those who receive placebo and will have improved postoperative hemodynamics and less postoperative morbidity. We further hypothesize that steroids work by diminishing the patients'inflammatory response to cardiovascular surgery and bypass and also treat the adrenal suppression brought on by intraoperative steroids and cardiopulmonary bypass. SPECIFIC AIMS The purpose of the protocol is to obtain prospective data about postoperative corticosteroid use in neonates with congenital heart disease. Our hypothesis is that postoperative treatment with corticosteroids will allow weaning of inotropic agents and improve postoperative hemodynamics. This will lead to earlier central venous line removal, shorter ICU admissions and less postoperative morbidity. Most infants and neonates who undergo cardiac surgery involving bypass and circulatory arrest receive intraoperative steroids, which can suppress adrenal function. Adrenal suppression is treated with stress dose steroids and we hypothesize that this is one of the methods that postoperative corticosteroids are efficacious. ACTH and cortisol levels will be assessed before and after corticosteroid dosing to determine an effect. We further hypothesize that steroids improve hemodynamics by diminishing the inflammatory response to bypass and cardiovascular surgery and the associated capillary leak syndrome. This will be assessed by checking TNF-alpha levels before and after corticosteroid dosing. Information in reference to the postoperative effects of corticosteroids could lead to increased use in the pediatric cardiac postoperative population. This may lead to improvements in postoperative outcome in critically ill neonates and limit the adverse effects of cardiopulmonary bypass and high dose inotropes. Before more widespread use can occur there must be further information about the benefits and risks of this strategy. The results can hopefully be used to substantiate the need for larger trials using corticosteroids postoperatively both to further study effectiveness and method of action. This protocol will aid in determining the method of action of corticosteroids in improving hemodynamics. This could possibly lead to more specifically targeted therapies to treat low cardiac output syndrome. The results will also aid in furthering our knowledge about the effects of cardiopulmonary bypass and cardiovascular surgery on the inflammatory cascade and the endocrine axis. The field of pediatric cardiovascular intensive care is evolving at a rapid rate and heading towards a time when treatments will be directed at the cellular level such as inhibition of the inflammatory cascade. The results of this research will give us some information about one possible target for treatment.